The mstpNewRootPort trap indicates that the sending agent has changed the root Port of the Spanning Tree in the CIST or in any MSTI. If the instance has become a root one, the sending value of the parameter mstpXstPortIndex is equal to zero. The trap is sent by a bridge soon after its election as the new root Port, e.g., upon expiration of the Topology Change Timer immediately subsequent to its election. Implementation of this trap is optional.